Some collectables are antiques, others are classed as retro, vintage or curios but all are of value to the collector. In any of these fields, buyers seek out rarities and items with specific associations.

Three and a half years ago Welsh saleroom Rogers Jones set a world record for a rugby shirt at auction when a jersey from the 1905-06 New Zealand tour to the UK made £180,000 – and now another All Blacks shirt from that era is on offer from the same auction house.

An unopened copy of the classic video game Super Mario Bros set a new auction record when it recently sold in Dallas, Texas for $80,000 (£62,000). The game is the only known sealed example from a test market release in 1985.

Anniversaries can tempt out collections to auction but it can have a longer-lasting effect. Last year marked the centenary of votes for women in Britain and a lot coming up in 2019 shows the consignments are still out there.

It’s not every day you see an auctioneer holding a 5ft 6in (1.67m) long sperm whale penis. Then again, it’s not every day that you see the sort of lots that are offered in Sworders’ Out of the Ordinary auction.

In the latest of our occasional series of collector interviews, we talk to Musa Igrek, who won the ABA Book Collecting Prize 2018 for his assemblage of secretly funded government-sponsored works during the Cold War.

Shown below is a page from an 1897 Paris edition of Robert de Flers’ 'Ilsée, Princesse de Tripoli' in which the text is framed by 132 coloured litho illustrations, borders and other decorations by Alphonse Mucha.

Every collecting field starts out with a broad umbrella title: classic cars, for instance. Easy. However, as you descend through the levels it not only drops into sub-sections, but veers off to the side, so you also get automobilia, the ephemera surrounding those cars.